Grazing North Texas: Purple Threeawn

By Tony Dean | tonydean.tx1@gmail.com

Purple threeawn is a short-lived perennial grass that is native to the western two-thirds of the United States, and can be found in Northern Mexico and Southern Canada. This species has been separated in the past into several distinct species. The PLANTS Database currently recognizes a single species with five varieties. There are about 11 varieties of threeawns in Texas, with about half being annual and half of them perennial. These bunch grasses can grow from six to 20 inches in height and are adapted to most soil types.


Perennial threeawns are among the early plants to green up each year and provide limited grazing for a few weeks until seeds begin to develop. The leaves of most threeawns are flat, slender, and often curled near the end. The common identification trait of all threeawns is the presence of three small awns arranged like helicopter blades above each seed. In some threeawn species, these awns can irritate the eyes, mouth and throat of grazing animals. If you’ve ever walked through a field of mature threeawn while wearing low quarter shoes and socks, you will find that threeawns can irritate people, too, by sticking in your socks.

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